Platinum-based chemotherapeutics exert their therapeutic efficacy via the formation of DNA adducts which interfere with DNA replication, transcription and cell division and ultimately induce cell death. Repair and tolerance of these Pt-DNA lesions by nucleotide excision repair (NER) and homologous recombination (HR) can substantially reduce the effectiveness of therapy. Inhibition of these repair pathways, therefore, holds the potential to sensitize cancer cells to Pt treatment and increase clinical efficacy. Replication Protein A (RPA) plays essential roles in both NER and HR, along with its role in DNA replication and DNA damage checkpoint activation. Each of these functions is, in part, mediated by RPA binding to single-stranded DNA (ssDNA). Here we report the synthesis and characterization of novel derivatives of RPA small molecule inhibitors and their activity in models of epithelial ovarian cancer (EOC) and non-small cell lung cancer (NSCLC). We have synthesized analogs of our previously reported RPA inhibitor TDRL-505 and determined the structure activity relationships. These data led us to the identification of TDRL-551, which exhibited a greater than 2-fold increase in in vitro activity. TDRL-551 showed synergy with Pt in tissue culture models of EOC and in vivo efficacy, as a single agent and in combination with platinum, in a NSCLC xenograft model. These data demonstrate the utility of RPA inhibition in EOC and NSCLC and the potential in developing novel anticancer therapeutics that target RPA-DNA interactions.

[reaction: see text] The synthesis of an advanced intermediate in the synthesis of the title compound has been achieved. Key steps include an Ireland-Claisen rearrangement to install the C7 tertiary alcohol stereocenter, an SN2' reaction of an alkoxymethyl Cu reagent, and a diastereoselective Re-catalyzed allylic alcohol transposition.

A novel Claisen rearrangement in which the Breslow intermediate is engaged as a hydroxy-substituted N,S-ketene acetal to provide complex 3° alcohols without the use of organometallic reagents is reported. The reaction constitutes an unprecedented reactivity mode for the Breslow intermediate.

The method presents advantages over the known procedures. It does not require cryogenic conditions as those applying organo Li or Mg nucleophiles, and is compatible with acidic and electrophilic functional groups in contrast to the methods using 2-lithiothiazoles or benzothiazoles. The presented reaction tolerates aromatic and heteroaromatic substituents and even challenging unprotected phenol [cf. (IIId)] and is scalable. No reaction takes place when 4-nitrobenzaldehyde is used affording only the Cannizarro product. -(ALWARSH, S.; AYINUOLA, K.; DORMI, S. S.; MCINTOSH*, M. C.; Org. Lett. 15 (2013) 1, 3-5, http://dx.doi.org/10.1021/ol303053c ; Univ. Ark., Fayetteville, AR 72701, USA; Eng.) -Y. Steudel 21-147